No, it’s not a new email client for OS X or iOS. It’s something better: a future^[1] company based in Switzerland providing a completely secure email service. They have launched a campaign on Indiegogo and aim to raise $45,000 by the end of April 2014.

You should follow the link and read what they’re offering in detail. Here are the bits that I’ve found essential (emphasis theirs):

We will provide you with an e‑mail address with the strongest privacy protection on the World: no one will be able to read your emails (including us), but you.

[…]

We will use servers physically placed in Switzerland and under our own direct control: no cloud computing, no outsourcing. We will only make use of open source software: no backdoors for corporations and governments.

[…]

We will employ cryptography everywhere — when receiving, sending, and storing email, as well as on our website, including e‑commerce pages and webmail.

If you want to, we will encrypt your whole mailbox. This means that no one will be able to read your emails including us.

They offer a wide range of account options, from a basic email account that’ll cost you $15/year (100MB email storage) to a $99/year Business account where you can bring your domain to Mail Shield and the company will offer infinite aliases and SMTP service, plus 1GB of email storage. There are more expensive options if you want full encryption of your mailbox. 

I personally know one of the engineers involved in this project and I can guarantee these are serious people. At the time of writing they have raised about $300. Please consider supporting Mail Shield or at least spread the word. I want this project to succeed.